DIYers try to recreate CREE vs Gravita?

Okay, guys. I know HPS vs LED is a hot topic, but I posted in the LED forum, I told you guys that I was concerned about heat. And if I am discussing what direction to go on a higher end DIY LED build, I certainly have no plans to go backwards , recreating my first grows with T5s and CFLs. Sorry, HPS and fluorescents really aren't the direction I am looking for.....been there, done that. (And if I had to factor in the cost of a discrete, portable a/c unit for that gravita...the price difference would be blown away within the first grow.)

I won't say that money is not an issue, I don't want to be wasteful, but if I end up spending $1500 I really don't give a fuck.

@Rider509 I have heard of Quantum boards, but like I said, I have been completely out of the loop for the last few years. And I mean completely out of the loop, my daughter is now 2 and all of the time that I would have spent growing, reading boards, and planning out future spaces has been replaced with diapers, feedings, nursery rhymes, and other tasks appropriate for my little mini me. I don't intend for this to be my last light, and maybe comparing to the spider was a poor choice. I was thinking 3 long bars across the space.....maybe with the central bar larger. I don't think I want all white lights, but I guess I am looking more for a discussion on the advantages and disadvantages of the different styles of LEDs - from the prospective of those who have grown with them. The technology has passed me by, while I have been focusing on the role of Mommy. Now that she is getting a little bigger, and we have a bigger home, I'm ready to get my feet wet.

AliCakes said:

Okay, guys. I know HPS vs LED is a hot topic, but I posted in the LED forum, I told you guys that I was concerned about heat. And if I am discussing what direction to go on a higher end DIY LED build, I certainly have no plans to go backwards , recreating my first grows with T5s and CFLs. Sorry, HPS and fluorescents really aren't the direction I am looking for.....been there, done that. (And if I had to factor in the cost of a discrete, portable a/c unit for that gravita...the price difference would be blown away within the first grow.)

I won't say that money is not an issue, I don't want to be wasteful, but if I end up spending $1500 I really don't give a fuck.

@Rider509 I have heard of Quantum boards, but like I said, I have been completely out of the loop for the last few years. And I mean completely out of the loop, my daughter is now 2 and all of the time that I would have spent growing, reading boards, and planning out future spaces has been replaced with diapers, feedings, nursery rhymes, and other tasks appropriate for my little mini me. I don't intend for this to be my last light, and maybe comparing to the spider was a poor choice. I was thinking 3 long bars across the space.....maybe with the central bar larger. I don't think I want all white lights, but I guess I am looking more for a discussion on the advantages and disadvantages of the different styles of LEDs - from the prospective of those who have grown with them. The technology has passed me by, while I have been focusing on the role of Mommy. Now that she is getting a little bigger, and we have a bigger home, I'm ready to get my feet wet.

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I'm late to the party here so please forgive me.

What is the first priority for light, which space, the 4x4 for flower? Does COB's interest you more than the QB boards, or vice versa etc?

I have grown with a lot of different lights and am about to start a COB vs QB grow in separate 3x3's because my 600W HPS ballast blew out a couple of days ago. The 600w Blue MH in particular is one of my favorite lights. BUT, I am open to test other lights as well and enjoy seeing the results first hand. I can see where you're coming from because I have been there. I think you guys could easily do a DIY for either typpe of LED tech, or go with some of the kits where you just frame something in etc.

The QB light I have right now is imporessing me more than any COB I have used in the past, but tomorrow my new COB's arrive that will be run against this light. Let's help you guys get sorted out here huh?

MeGaKiLlErMaN said:

Nooo you miss read, or I miss typed.. PPFD in a 4x4. Not PPF.

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800 ppfd in a 4x4 = 1200 ppf

CobKits said:

800 ppfd in a 4x4 = 1200 ppf

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Hey I only measure 745ppfd with a de1000w at 2 ft. It's not that great. I think they forget the light falloff when they run those tests.

im just saying math wise if you had an actual 800 ppfd over 4x4 area it would be 1200 ppf

CobKits said:

im just saying math wise if you had an actual 800 ppfd over 4x4 area it would be 1200 ppf

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Yes but since it's more spread out you get a higher PPFD which is the only important number.

Rahz said:

I've been around since the Vero gen5 and CXA days. Back then the Vero 18s were running about 35% efficient at nominal current. I know of a 720w rig that was pulling over 2 lbs at 35% efficiency. That was 1.25 GPW and isn't overly impressive compared to other examples. Around a year and a half ago people started building 50% efficient lamps and I started selling them. My current lamps are 57% efficient at full power. The story has changed over the years and only gotten better for LED. My 300w LED meant to cover a 2x4 provides 970 PPFD at full power and can easily hit 55 g/sqft since that's what achieved with the 35% efficient lamps.

I don't get butt hurt about it because I have seen it and know but don't care to have an emotional investment in trying to convince others. By the same token, there is still a price premium for good LED lamps and even kits at startup. It does pay off through electrical cost over years OR produce more for a given wattage but if a person get's what they need and electrical use isn't a concern they may not find that overly impressive.

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.
I was bored last night and was searching the old LED threads so I could be aware of the history behind the LED evolution. As far as RIU, I was smiling pleasantly when I saw Rahz, asking driver questions and nooby stuff. This was mid 2013. All the DIYers were building with star leds. I also read one that asked the future of LEDs. tripped me out, but one dude was talking about cxa 20 w leds, but people didn't understand how to dissipate all the heat from these Multi diode leds. Know your history folks. I felt the consensus was LED would never be the primary light for FLOWERING. Even I believed it. It slowly began to take over my room. First for veg, now for flower. I think its kinda cool to see how a lot of the LED OGs here, started off with blurple. It gives me hope that I can do what these guys have for others. Maybe even start a lighting company!
Also, Rider, why does it seem inconceivable that we'd use these lights for 5-10 years? In the last decade I have been stuck with hps. Ive always hated it. The heat, the color, bulb changes, hood cleanings, etc. But I stuck with it cuz it worked! When my 400 ballast took a crap I got a 600w. Then digi ballasts came out, I got one of those. Then cooled hood. Then enhanced bulbs. Then.... Point being, I used it cuz that was all I knew. All I trusted, all anyone that ever grew cannabis had used with good results that could be repeated by anyone with a greenish thumb. Efficiencies being where there at, how much better can light get? It would have to be SIGNIFICANTLY BETTER, (dare I say) impossibly better for me to start to Hate my led, like that damn hps.
Thank you to all the LED gurus paving the way.

Hps Stands For Hot Piece Of Shit!!!!!!!!!!!!!!!! This Is From A 70'S Metal Halide Grower Rock On Led

I flower in a tent with about 12 sq ft and veg in 4. I've used hps, mastercolor cmh, cfls, high end blurple LEDs and COBs over 9 years. At this point, nothing is capable of outdoing COBs or boards for that kind of garden area. Some of my COBs are a bit dated but not worth updating yet as they do so well and increases in efficiency will decrease as the ultimate efficiency possible is approached.

COBs and boards are also much easier to live with than HID heaters with pitiful spectrums.

It's also really nice to be around beautiful white light and not feeling like being in an over lit parking lot. Just not having to experience blurple is worth the investment.

MeGaKiLlErMaN said:

Yes but since it's more spread out you get a higher PPFD which is the only important number.

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That's why clever people use reflective materials to keep the light in. So there is no point in comparing HPS dark room measurements measuring only half the light (if it isn't even less).

A Gavita DE can easily give 800PPFD over a 2m2 area.

Wouldn't a 750W Gavita DE be more practical for a 4x4? 1000W's are supposed to go in 5x5 tents.

wietefras said:

That's why clever people use reflective materials to keep the light in. So there is no point in comparing HPS dark room measurements measuring only half the light (if it isn't even less).

A Gavita DE can easily give 800PPFD over a 2m2 area.

Wouldn't a 750W Gavita DE be more practical for a 4x4? 1000W's are supposed to go in 5x5 tents.

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My 5x5 measurement at 3ft got 258 PPFD... not really that good for flower. Thats the recommended height. its a bit higher at 2.5-2ft but the light doesnt go past the 4x4 area by much.

@MeGaKiLlErMaN, Indeed, those are the measurements that are completely and utterly useless. Unless you actually do grow in a very large dark room with no reflective walls. For the live of me I don't understand why people keep posting that nonsense.

A sane person does something to keep the light in. In a proper grow tent or room you do get 800PPFD. Not 233.

wietefras said:

@MeGaKiLlErMaN, Indeed, those are the measurements that are completely and utterly useless. Unless you actually do grow in a very large dark room with no reflective walls. For the live of me I don't understand why people keep posting that nonsense.

A sane person does something to keep the light in. In a proper grow tent or room you do get 800PPFD. Not 233.

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I have two sides that have panda film and and at 2ft I got 430.5PPFD. Its really not. I took them myself, Fact is they are awesome as long as they have overlap, without it they are meh.

@MeGaKiLlErMaN, Fact is, I have seen a guy measure it in a reflective 5x5 tent with a LiCor and he did get around 800PPFD.

Panda film looks like a poor choice for reflective material. Matt white stuff is only applicable for reflection in all directions. Not for sending light through on the same path (towards the plants!). Going by your data, this foil performs very poorly.

Also your light sensor seems to work very poorly with shallower light angles. It obviously does not have proper cosine correction. Just see how much more light they see in the test in a dark room compared to your measurements. You measure only about half the light intensity near the edges compared to the Growers House matrix where they use no walls at all. Doesn't that give you a clue that something is wrong with your measurements?

Either way, what CobKits said is how it works. PPFD=PPF/m2. Minus wall losses. Panda film might give you high wall losses, but if you have more direct reflective stuff that sends the light to the plants instead of a diffuse reflection which sends it in all directions (ie half of it back to the lamp and ceiling) then you can get 800PPFD.

wietefras said:

@MeGaKiLlErMaN, Fact is, I have seen a guy measure it in a reflective 5x5 tent with a LiCor and he did get around 800PPFD.

Panda film looks like a poor choice for reflective material. Matt white stuff is only applicable for reflection in all directions. Not for sending light through on the same path (towards the plants!). Going by your data, this foil performs very poorly.

Also your light sensor seems to work very poorly with shallower light angles. It obviously does not have proper cosine correction. Just see how much more light they see in the test in a dark room compared to your measurements. You measure only about half the light intensity near the edges compared to the Growers House matrix where they use no walls at all. Doesn't that give you a clue that something is wrong with your measurements?

Either way, what CobKits said is how it works. PPFD=PPF/m2. Minus wall losses. Panda film might give you high wall losses, but if you have more direct reflective stuff that sends the light to the plants instead of a diffuse reflection which sends it in all directions (ie half of it back to the lamp and ceiling) then you can get 800PPFD.

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Possibly, Ill get a better meter to check these measurements again in time, however even at 1ft I didnt get over 800. I watched a comparison between the Par meters and there wasnt a big difference. Not sure why the light source would make a huge difference.

The light source probably doesn't make the difference, but the angles do. Light sensors are less sensitive to light arriving at a shallow angle compared to light hitting it straight in the face. A cosine correction is supposed to lessen that effect. Although you give no sizes for the matrix so it's hard to correlate these measurements to other matrices.

Your COB measurements look very low too though. Oddly enough to pretty much the same degree as the HPS. Although your HPS uniformity is nowhere near what I measured (with a lux meter though) or what others have measured with PAR meters.

Anyway, Lets try a more practical approach then. I would get over 1200g from one Gavita 1000W DE (@ 1150W draw) in a 5x5 tent. After converting to COBs, I need 800W of Cree COBs ("old" 3000K AB bin) to achieve the same yield in roughly the same surface area. So I would agree with you that a Gavita 1000W is comparable to 800W of a year old COBs. Although I doubt they are supplying only 440umol/s/m2 to the plants.

The current COBs are a lot more efficient, so probably 750W or even 700W would be enough nowadays.

wietefras said:

The light source probably doesn't make the difference, but the angles do. Light sensors are less sensitive to light arriving at a shallow angle compared to light hitting it straight in the face. A cosine correction is supposed to lessen that effect. Although you give no sizes for the matrix so it's hard to correlate these measurements to other matrices.

Your COB measurements look very low too though. Oddly enough to pretty much the same degree as the HPS. Although your HPS uniformity is nowhere near what I measured (with a lux meter though) or what others have measured with PAR meters.

Anyway, Lets try a more practical approach then. I would get over 1200g from one Gavita 1000W DE (@ 1150W draw) in a 5x5 tent. After converting to COBs, I need 800W of Cree COBs ("old" 3000K AB bin) to achieve the same yield in roughly the same surface area. So I would agree with you that a Gavita 1000W is comparable to 800W of a year old COBs. Although I doubt they are supplying only 440umol/s/m2 to the plants.

The current COBs are a lot more efficient, so probably 750W or even 700W would be enough nowadays.

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Its all about height. But Ill re test in the future and compare.

I have a test going with this same setup, except using Citizen CLUo58's https://www.rollitup.org/t/test-room-de-hps-vs-citizen-cobs.935306/. The only part that sucks is, I only get up there to take pictures every other week. I am hoping to go tomorrow.

Also, going through all his rooms, DE and SE, center under the light was always 200,000 lux, so this is the target after stretch is done.